US4776692A - Testing light transmitting articles - Google Patents

Testing light transmitting articles Download PDF

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Publication number
US4776692A
US4776692A US06/779,572 US77957285A US4776692A US 4776692 A US4776692 A US 4776692A US 77957285 A US77957285 A US 77957285A US 4776692 A US4776692 A US 4776692A
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Prior art keywords
image
article
pattern
computer
spacial
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Expired - Fee Related
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US06/779,572
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English (en)
Inventor
Roy S. Kalawsky
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BAE Systems PLC
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British Aerospace PLC
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Assigned to BRITISH AEROSPACE PUBLIC LIMITED COMPANY reassignment BRITISH AEROSPACE PUBLIC LIMITED COMPANY ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: KALAWSKY, ROY S.
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/88—Investigating the presence of flaws or contamination
    • G01N21/95—Investigating the presence of flaws or contamination characterised by the material or shape of the object to be examined
    • G01N21/958—Inspecting transparent materials or objects, e.g. windscreens
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/88—Investigating the presence of flaws or contamination
    • G01N21/95—Investigating the presence of flaws or contamination characterised by the material or shape of the object to be examined
    • G01N21/958—Inspecting transparent materials or objects, e.g. windscreens
    • G01N2021/9586—Windscreens

Definitions

  • This invention relates to a method and system for testing the optical quality of light transmitting articles. More particularly, but not exclusively, it relates to the evaluation of aircraft transparencies, such as cockpit canopies, with respect to the optical distortion caused by them.
  • Aircraft cockpit canopies can comprise manufacturing irregularities which produce localised distortion of the view seen through them.
  • prismatic errors or localised variation in surface parallelism can produce angular deviation between the true and observed positions of an object seen through the canopy.
  • the problem is more acute for the curved canopies having low inclinations to the horizontal which are fitted to modern high speed aircraft--with these, the angular deviation errors may vary widely with the angle of observation and the pilot's eye position. They can also introduce so-called binocular disparity effects.
  • the array outputs are fed via a selector switch to a display unit which, by the position of a spot of light along an elongate display area, shows up any displacement of the projected image from the centre of the selected array.
  • This is a point testing technique--after the test of a particular point of the canopy, the canopy is moved to test another point and so on. This takes time and requires care by a specially trained operator--also, since it requires that the two arrays be correctly positioned relative to the beam-splitter and projector, the initial alignment of the apparatus may be difficult to achieve.
  • a method of testing the optical quality of a light transmitting article comprising using an image sensor to form a signal representative of an image of a two-dimensional pattern viewed through the article to be tested, storing a series of digital signals representative of respective pixels of said image in a memory and using a computer means connected to said memory to evaluate said digital signals to sense the presence in said image of predetermined features of the pattern and to calculate deviations in shape and/or position of said features due to the presence of said article.
  • apparatus for testing the optical quality of a light transmitting article comprising a member bearing a two-dimensional target pattern, image sensor means positioned for viewing said pattern, support means for supporting said article between said pattern and said image sensor means, digitiser means connected to said image sensor means for forming a series of digital signals representative or respective pixels of the image received by the sensor means, frame store means connected to the digitiser means for storing said digital signal, and computer means connected to the frame-store means and operable to evaluate said signals and to calculate deviation in shape and/or position of predetermined features of the pattern due to the presence of said article.
  • a method for testing the optical quality of a light transmitting article comprising using an area-imaging device to form a video signal indicative of a scene as viewed by the device through said article, and using computer means to check said video signal against parameters indicative of the view which would be seen by said device if the article were not present and to produce via output means connected to the computer an indication of discrepancies between the video signal and said parameters.
  • Said parameters can be embodied in stored video signal form by the device with said article absent, or the parameters can comprise calculated data indicative of the view expected to be seen by the device when the article is not present.
  • said output means comprise a video display monitor upon which the computer is operable to produce a picture of said scene as viewed via the article with said discrepancies indicated by some easily seen variation of the picture.
  • the colour or brightness of the picture may vary with the degree of deviation between the video signal and the parameters.
  • apparatus for testing the optical quality of a transparent article comprising an area-imaging device for forming a video signal indicative of a scene viewed by the device via said article, computer means for checking said video signal against parameters indicative of the view which would be seen by the device if the article were not present, and output means for making available an indication of any discrepancies between the video signal and said parameters.
  • a television camera is arranged to view a target scene, comprising a cross-hatch pattern, for example, respectively directly and then via the article to be tested, an aircraft cockpit canopy for example, the camera output being supplied to a ⁇ frame grabber ⁇ which digitises one frame of the video signal formed with the canopy not present and then a frame of the signal formed when the canopy is present.
  • the two sets of digital pixel signals are stored in a frame store and the corresponding pixel signals are compared by a digital computer.
  • the magnitudes of any deviations are digitised and used to control the brightness or colour of corresponding elements of a picture produced by a T.V. monitor.
  • FIG. 1 is a block diagram of apparatus for testing an aircraft cockpit canopy
  • FIGS. 2A and 2B are diagram for explaining distortion measurement.
  • the apparatus to be described provides a facility for testing the optical quality of light transmitting articles.
  • the method employs an image sensor to convert the optical distortions, spacial deviations, etc., into a video signal.
  • This video signal is then digitised and stored within a computer.
  • the type and arrangement of the sensor depends on the resolution required for a given application, although the processing techniques remain the same.
  • the optical quality analysis produced by the system can be output in numerical form or with the optical distortions displayed on a visual display monitor, perhaps reinforced by means of colour. The form of output is again dependent on the applications. Provision is made whereby the video signal describing the ⁇ distorted image ⁇ can be stored in digital form onto magnetic media, eg, floppy disk.
  • FIG. 1 illustrates the apparatus required for testing aircraft transparencies/canopies.
  • the apparatus comprises a television camera 1 which is set up to view a standard target 2 having some suitable form of cross-hatch pattern formed thereon.
  • an image digitiser 4 connected to the computer, stores one complete frame of the video signal in a framestore 5.
  • a television display 6 simultaneously displays the contents of the framestore thereby enabling the camera to be focussed correctly if necessary.
  • the computer 7 measures the vertical and horizontal spacings of the test pattern so as to produce a mask which is compared with the image obtained via the canopy. For this, the canopy is placed in position such that the camera is at the design eye position. Another image is captured and stored. The mask is then compared with the stored image. The result of the comparison could be displayed in the form of a numerical read-out either on the monitor 6 or on a printer 8.
  • the monitor could be photographed, or the contents of the framestore stored on disk, tape or the computer could be programmed to permit the reproduction of say, a grey-scale printed copy of the framestore contents on the printer 8.
  • the television camera 1 could be replaced by some other imaging device, for example charge-coupled device line arrays or area arrays.
  • the computer 7 is rendered operable to evaluate an image viewed via the canopy against predetermined parameters programmed into the computer.
  • the target 2 carries a two-dimensional cross-hatch pattern, ie a series of horizontal and vertical straight lines forming a grid made up of squares one of which is shown in FIGS. 2a and 2b.
  • a single image frame from the camera 1 is digitised by digitiser 4 and the resultant series of digital pixel signals are stored in the frame store 5.
  • the computer 7 then addresses the locations of the store 5 so as, in effect, to track across the image in a predetermined direction.
  • the computer might address first the store location containing the signal representative of the pixel at the top, left hand corner of the image, then the location of the pixel which is one row down and one column across, then the location in the third row and third column, and so on, in effect tracking a diagonal line crossing the image from its top, left hand corner.
  • the computer evaluates the signal therein.
  • the computer will reach a location containing a signal representative of the colour of the lines of the pattern, ie it may have found a portion of one of the lines of the pattern or, alternatively, it may just have found some background blemish.
  • the computer addresses in turn locations around the line-colour-level containing location.
  • the computer compares each of these lengths with the known values A,B,C,D,E,F,G, and H respectively for an undistorted square, as shown in FIG. 2a, so as to achieve, for each, an error.
  • a series of error values E A
  • , E B
  • , E C
  • - - - E H
  • the error values can be simply summed and the magnitude of the sum then represents, inversely, the quality of that portion of the canopy.
  • only a single, correct value of length needs to be available to the computer since, for a square as shown in FIG.
  • the lengths A,B,C,D,F and H are all equal while G and E are each equal to that length multiplied by half the square root of two.
  • the computer could only measure the lengths A,B,C,D,E and G in FIG. 2a if desired. However, it is preferred to measure the mid-point widths F and H also because it helps to reduce sampling errors--also the distortion may have the effect of making the lines appear curved.
  • the computer may be desireable for the computer to be able to evaluate the errors in each square of the target pattern without any pre-knowledge of the relevant dimensions--this enables the apparatus to be used without the assurance to say a fixed spacing between the camera and target, magnifications of the camera lens, and so on.
  • This can be done because of the above-mentioned relationship between the lengths, ie because of the fact that A,B,C,D,F and H are all equal while G and E each equal the value of say A times half the square root of two, provided the square is undistorted.
  • the computer can simply form error values representing the deviation of each value from a norm derived from the other values and then form an overall merit value as before.
  • the computer 7 may track the lines of the image as described above and, for each, generate an equation representative of the line as a polynomial fit. By then correlating that polynomial with the equation of a straight line, the deviation from straightness of each part of the observed line can be determined.
  • This is a known mathematical technique which, by way of example, is described at section 20.20 ( ⁇ Regression Analysis ⁇ or fitting curved onto straight lines) of the book Advanced Engineering Mathematics by Erwin Kreyszig--4th Edition, 1979, Wiley. Its application to the context of the present invention will be well within the scope of those skilled in the art of computer imge analysis.
  • Additional signal processing can include edge enhancement to accentuate pattern boundaries, grey-level thresholding (so as to reduce any adverse effects of light reflection from the camera side of the canopy, say).
  • Edge tracking and chain code techniques can be used to determine the mask and image deviations and so on. Zoom lenses could be used to magnify the area of interest if desired with a consequential increase in resolution.
  • the computer could replace the contents of the frame store 5 by a series of digital signals representing the figures of merit which it has obtained for each portion of the image so that then the monitor 6 will display a picture representative of the optical quality of the canopy.
  • the different merit values could be represented by different colors of the picture, eq the colour red could represent high distortion.
  • store content could be modified so that the resulting displayed picture still represents the viewed image while at the same time showing the pattern of distortion.
  • the brightness of the display could be modulated in accordance with the target image while its colour (hue) could be varied to highlight areas of distortion.
  • the computer 7 will itself evaluate the canopy as a whole, according to predetermined rules, and the indicate whether or not the canopy is acceptable.
  • the rules are, of course, selectable. For example, it may be that no high distortion portions are permissible, or that some distortion is allowable provided it is confined to certain areas, and so on.
  • the illustrated apparatus is rendered operable so than an image can be taken and evaluated from each design eye position of the pilot.
  • the support for the canopy 3 could be arranged to permit the canopy to be moved relative to the camera 1 and target 2 between respective pre-settable positions horizontally spaced by the distance between the average person's eyes, the camera and canopy being of course set up so that the camera is about where the pilot's head would be relative to the canopy in the eventual aircraft. Then two evaluations can be made, one for each eye position.
  • This preferred feature is important because, as mentioned earlier, the canopies used for modern aircraft can produce effects which vary quite widely from one to the other eye of the pilot.
  • the illustrated apparatus can incorporate an unpolarised light source and a polarimeter (not shown) arranged for the polarimeter to receive light from the source after reflection from the canopy and thereby to show up variations in the polarisation effect afforded by different portions of the canopy.
  • a polarisation test may better show up effects such as localised hazing of the canopy, ie surface finish defects perhaps caused by polishing of the canopy, curvature deviations, and even residual stresses in the canopy material which may be a source of structural weakness or might produce rainbow effects to the pilot.
  • the polarimeter could take one of the forms disclosed in U.K. Patent Specification No. 1,472,854 for example, ie it can comprise one or two T.V.
  • the camera tubes providing respective image signals seen via orthogonally polarising filters--if one camera is used the images are formed successively via a movable filter--along with processing circuits which combines the image singals to form a further signal representative of the polarisation at different points of the image.
  • the polarisation pattern can then be displayed representing variations in polarisation.
  • the camera 1 in drawing FIG. 1 of the present specification could form the or one of the cameras of the polarimeter by being provided with a suitable removable polarising filter (not shown) and by having suitable image signal processing circuits (not shown) able to be switched into the system.
  • the computer 7 may be able to be programmed to carry out the processing of the two images, taken with orthogonal polarisations so as to form the polarisation pattern image.
  • the polarisation pattern image could then simply be displayed on monitor 6 or, preferably, the computer 7 is operable to evaluate it eg by comparing each resulting pixel signal value stored in store 5 against known acceptable values.
  • a linear imaging array can be used and the area image captured and analysed one line at a time, the canopy or the sensor itself being moved by an appropriate between-line distance following each capture of an image line.

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  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
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  • Life Sciences & Earth Sciences (AREA)
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  • Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)
US06/779,572 1984-09-24 1985-09-24 Testing light transmitting articles Expired - Fee Related US4776692A (en)

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Cited By (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5006722A (en) * 1990-03-02 1991-04-09 Intec Corp. Flaw annunciator with a controllable display means for an automatic inspection system
USH999H (en) 1990-09-13 1991-12-03 The United States Of America As Represented By The Secretary Of The Air Force Transparency distortion measurement process
US5184190A (en) * 1991-05-28 1993-02-02 Winzen International, Inc. Method and apparatus for detecting flaws and defects in heat seals
US5296705A (en) * 1991-07-23 1994-03-22 Thomson-Csf Imaging system with integrated measuring of the wear of its optical elements working in transmission mode and optronic imaging equipment comprising an imaging system such as this
US5343288A (en) * 1992-11-23 1994-08-30 Libbey-Owens-Ford Co. Optical evaluation of automotive glass
US5446536A (en) * 1992-05-06 1995-08-29 Nippon Sheet Glass Co., Ltd. System of detecting optical distortion of a light-transmitting plate-like member
US5471297A (en) * 1993-08-31 1995-11-28 Asahi Glass Company Ltd. Method of and apparatus for measuring optical distortion
EP0685733A1 (fr) * 1994-06-02 1995-12-06 Saint-Gobain Vitrage Procédé de mesure de la qualité optique d'un vitrage
US5533139A (en) * 1992-05-29 1996-07-02 Eastman Kodak Company Coating density analyzer and method using image processing
US5621520A (en) * 1996-05-13 1997-04-15 Northrop Grumman Corporation Transparency inspection method for blurriness in vehicle windscreens with elastomeric liners
US5657161A (en) * 1995-11-15 1997-08-12 Northrop Grumman Corporation Dual polarized filters to eliminate canopy reflections
US5812260A (en) * 1995-10-16 1998-09-22 Corning Incorporated Method and system for measuring optical distortion
US6100990A (en) * 1999-06-14 2000-08-08 Ford Motor Company Method and apparatus for determining reflective optical quality using gray-scale patterns
US6208412B1 (en) 1999-06-14 2001-03-27 Visteon Global Technologies, Inc. Method and apparatus for determining optical quality
US20040057046A1 (en) * 2000-09-01 2004-03-25 Abbott Mark M. Optical system for imaging distortions in moving reflective sheets
WO2007135465A2 (fr) 2006-05-23 2007-11-29 Pilkington Group Limited Procédé d'inspection de vitrage
US20080225115A1 (en) * 2005-03-07 2008-09-18 Nippon Sheet Glass Company, Limited Perspective Distortion inspecting Equipment and Method of Translucent Panel
US7557918B1 (en) 2006-04-05 2009-07-07 Itt Manufacturing Enterprises, Inc. Spectral polarimetric image detection and analysis methods and apparatus
US20100086191A1 (en) * 2006-11-09 2010-04-08 Freeman Philip L Evaluation of optical distortion in a transparency
JP2016524708A (ja) * 2013-05-29 2016-08-18 イスラ サーフィス ヴィズィオーン ゲーエムベーハー 透明体の屈折力を決定する方法及びその装置
US20170048517A1 (en) * 2015-08-10 2017-02-16 Oren Aharon Mass production mtf testing machine
JP2022096043A (ja) * 2020-12-17 2022-06-29 株式会社トプコン 検査システム及び検査方法
JP2022096044A (ja) * 2020-12-17 2022-06-29 株式会社トプコン 画像処理方法及び画像処理装置
US20220343487A1 (en) * 2021-04-15 2022-10-27 The Boeing Company Method and apparatus for determining optical distortion of an object from a single image

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* Cited by examiner, † Cited by third party
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US7365838B2 (en) 2004-04-02 2008-04-29 Lockheed Martin Corporation System and method for the measurement of optical distortions
FR3124782B1 (fr) * 2021-06-30 2023-12-08 Saint Gobain Méthode d’analyse de la qualité optique d’un vitrage, méthode de calibration d’une caméra, vitrage analysé

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US2871756A (en) * 1953-12-28 1959-02-03 Northrop Aircraft Inc Mechano-optical method for inspecting transparent flat or contoured panels
DE2310763A1 (de) * 1973-03-03 1974-09-26 Ver Flugtechnische Werke Verfahren zur pruefung der optischen qualitaet transparenter scheiben
US3992571A (en) * 1973-05-11 1976-11-16 National Research Development Corporation Differential optical polarization detectors
GB1472854A (en) * 1973-05-11 1977-05-11 Nat Res Dev Differential optical polarisation detectors
US4249823A (en) * 1979-10-16 1981-02-10 The United States Of America As Represented By The Secretary Of The Air Force Windscreen angular deviation measurement device
US4299482A (en) * 1979-11-01 1981-11-10 The United States Of America As Represented By The Secretary Of The Air Force Measurement of windscreen distortion using optical diffraction
US4310242A (en) * 1980-04-01 1982-01-12 The United States Of America As Represented By The Secretary Of The Air Force Field test unit for windscreen optical evaluation
US4398822A (en) * 1981-12-03 1983-08-16 Task Harry L Two-axis angular deviation measurement system with target image rotating means
US4461570A (en) * 1982-06-09 1984-07-24 The United States Of America As Represented By The Secretary Of The Air Force Method for dynamically recording distortion in a transparency
US4641570A (en) * 1983-07-20 1987-02-10 Taiho Kogyo Kabushiki Kaisha Swash plate type compressor having a center cavity in surface of piston shoe
US4647197A (en) * 1983-01-12 1987-03-03 Nippon Sheet Glass Co., Ltd. Distortion inspection apparatus of a glass plate

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2871756A (en) * 1953-12-28 1959-02-03 Northrop Aircraft Inc Mechano-optical method for inspecting transparent flat or contoured panels
DE2310763A1 (de) * 1973-03-03 1974-09-26 Ver Flugtechnische Werke Verfahren zur pruefung der optischen qualitaet transparenter scheiben
US3992571A (en) * 1973-05-11 1976-11-16 National Research Development Corporation Differential optical polarization detectors
GB1472854A (en) * 1973-05-11 1977-05-11 Nat Res Dev Differential optical polarisation detectors
US4249823A (en) * 1979-10-16 1981-02-10 The United States Of America As Represented By The Secretary Of The Air Force Windscreen angular deviation measurement device
US4299482A (en) * 1979-11-01 1981-11-10 The United States Of America As Represented By The Secretary Of The Air Force Measurement of windscreen distortion using optical diffraction
US4310242A (en) * 1980-04-01 1982-01-12 The United States Of America As Represented By The Secretary Of The Air Force Field test unit for windscreen optical evaluation
US4398822A (en) * 1981-12-03 1983-08-16 Task Harry L Two-axis angular deviation measurement system with target image rotating means
US4461570A (en) * 1982-06-09 1984-07-24 The United States Of America As Represented By The Secretary Of The Air Force Method for dynamically recording distortion in a transparency
US4647197A (en) * 1983-01-12 1987-03-03 Nippon Sheet Glass Co., Ltd. Distortion inspection apparatus of a glass plate
US4641570A (en) * 1983-07-20 1987-02-10 Taiho Kogyo Kabushiki Kaisha Swash plate type compressor having a center cavity in surface of piston shoe

Cited By (32)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1991013343A1 (fr) * 1990-03-02 1991-09-05 Intec Corp. Indicateur de defauts pour systeme d'inspection automatique
US5006722A (en) * 1990-03-02 1991-04-09 Intec Corp. Flaw annunciator with a controllable display means for an automatic inspection system
USH999H (en) 1990-09-13 1991-12-03 The United States Of America As Represented By The Secretary Of The Air Force Transparency distortion measurement process
US5184190A (en) * 1991-05-28 1993-02-02 Winzen International, Inc. Method and apparatus for detecting flaws and defects in heat seals
US5296705A (en) * 1991-07-23 1994-03-22 Thomson-Csf Imaging system with integrated measuring of the wear of its optical elements working in transmission mode and optronic imaging equipment comprising an imaging system such as this
US5446536A (en) * 1992-05-06 1995-08-29 Nippon Sheet Glass Co., Ltd. System of detecting optical distortion of a light-transmitting plate-like member
US5533139A (en) * 1992-05-29 1996-07-02 Eastman Kodak Company Coating density analyzer and method using image processing
US5343288A (en) * 1992-11-23 1994-08-30 Libbey-Owens-Ford Co. Optical evaluation of automotive glass
US5471297A (en) * 1993-08-31 1995-11-28 Asahi Glass Company Ltd. Method of and apparatus for measuring optical distortion
EP0685733A1 (fr) * 1994-06-02 1995-12-06 Saint-Gobain Vitrage Procédé de mesure de la qualité optique d'un vitrage
US5812260A (en) * 1995-10-16 1998-09-22 Corning Incorporated Method and system for measuring optical distortion
US5657161A (en) * 1995-11-15 1997-08-12 Northrop Grumman Corporation Dual polarized filters to eliminate canopy reflections
US5621520A (en) * 1996-05-13 1997-04-15 Northrop Grumman Corporation Transparency inspection method for blurriness in vehicle windscreens with elastomeric liners
US6100990A (en) * 1999-06-14 2000-08-08 Ford Motor Company Method and apparatus for determining reflective optical quality using gray-scale patterns
US6208412B1 (en) 1999-06-14 2001-03-27 Visteon Global Technologies, Inc. Method and apparatus for determining optical quality
US20040057046A1 (en) * 2000-09-01 2004-03-25 Abbott Mark M. Optical system for imaging distortions in moving reflective sheets
US7345698B2 (en) 2000-09-01 2008-03-18 Litesentry Corporation Optical system for imaging distortions in moving reflective sheets
US20080225115A1 (en) * 2005-03-07 2008-09-18 Nippon Sheet Glass Company, Limited Perspective Distortion inspecting Equipment and Method of Translucent Panel
US7557918B1 (en) 2006-04-05 2009-07-07 Itt Manufacturing Enterprises, Inc. Spectral polarimetric image detection and analysis methods and apparatus
WO2007135465A2 (fr) 2006-05-23 2007-11-29 Pilkington Group Limited Procédé d'inspection de vitrage
WO2007135465A3 (fr) * 2006-05-23 2008-01-17 Pilkington Group Ltd Procédé d'inspection de vitrage
US20100232677A1 (en) * 2006-05-23 2010-09-16 Pilkington Group Limited Glazing inspection method
US8165382B2 (en) 2006-05-23 2012-04-24 Pilkington Group Limited Glazing inspection method
US20100086191A1 (en) * 2006-11-09 2010-04-08 Freeman Philip L Evaluation of optical distortion in a transparency
US7899236B2 (en) 2006-11-09 2011-03-01 The Boeing Company Evaluation of optical distortion in a transparency
JP2016524708A (ja) * 2013-05-29 2016-08-18 イスラ サーフィス ヴィズィオーン ゲーエムベーハー 透明体の屈折力を決定する方法及びその装置
US20170048517A1 (en) * 2015-08-10 2017-02-16 Oren Aharon Mass production mtf testing machine
US10142621B2 (en) * 2015-08-10 2018-11-27 Oren Aharon Mass production MTF testing machine
JP2022096043A (ja) * 2020-12-17 2022-06-29 株式会社トプコン 検査システム及び検査方法
JP2022096044A (ja) * 2020-12-17 2022-06-29 株式会社トプコン 画像処理方法及び画像処理装置
US20220343487A1 (en) * 2021-04-15 2022-10-27 The Boeing Company Method and apparatus for determining optical distortion of an object from a single image
US12293503B2 (en) * 2021-04-15 2025-05-06 The Boeing Company Method and apparatus for determining optical distortion of an object from a single image

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EP0176336A2 (fr) 1986-04-02
GB8424074D0 (en) 1984-10-31
EP0176336A3 (fr) 1987-08-19

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